Birth of new brain cells might erase babies’ memories

New neurons may explain why adults can’t remember being infants

WIPE OUT During infancy, in humans and some animals, a memory center of the brain called the hippocampus (blue) churns out new neurons (white). These cells may mess up early memories and could explain why adults can’t remember being babies or toddlers.

Courtesy of Jason Snyder

Unlike the proverbial elephants, babies always forget.

Infants’ memories may be wiped clean by the genesis of new brain cells, a study in rodents suggests. The findings offer an explanation for why people can’t recall memories from early childhood, a century-old mystery.

The study’s authors “make a very interesting and compelling case,” says neuroscientist and psychiatrist Thomas Insel, director of the National Institute of Mental Health in Bethesda, Md. “It’s just truly fascinating,” he says. “Nobody has actually looked at this very carefully before.”

More than 100 years ago, Sigmund Freud speculated that humans’ tendency to forget their early years, dubbed infantile amnesia, might have a psychosexual origin. Scientists later thought memories might be rooted in language, because kids typically start making long-term memories around the time they start speaking, says study coauthor Sheena Josselyn of

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